Commit Message

Motivation:
IBM Blue Gene/Q comes with some very strange firmware that I'm trying to get out of using in the kernel. So instead I spin all the threads in the boot wrapper (using the firmware) and have them enter the kexec stub, pre-translated at the virtual "linear" address, never touching firmware again.
This works strategy works wonderfully, but I need the following patch in the kexec stub.
I believe it should not effect Book3S and Book3E does not appear to be here yet so I'd love to get any criticisms up front.
This patch adds two items:
1) Book3e requires that GPR4 survive the "hold" process, so we make
sure that happens.
2) Book3e has no real mode, and the hold code exploits this. Since
these processors ares always translated, we arrange for the kexeced
threads to enter the hold code using the normal kernel linear mapping.
Signed-off-by: Jimi Xenidis <jimix@pobox.com>
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arch/powerpc/kernel/head_64.S | 19 ++++++++++++++++++-
1 files changed, 18 insertions(+), 1 deletions(-)